apply the bidi rule to every label of a bidi domain name in to_ascii

[Arawoof06]

is_label_valid only runs the RFC 5893 Bidi conditions on a label that has an RTL code point of its own, so the other labels of a Bidi domain name are never held to them and to_ascii accepts hosts such as ا.1x, x.1.א and ا.a- that UTS 46 (and whatwg-url, tr46, ICU) reject; only the URL standard's ASCII carve-out keeps xn--mgb.1x valid. to_ascii now classifies the mapped domain up front and validates every label with that flag, restarting the walk once when the RTL code points turn out to sit inside an ACE label of a non-ASCII domain. The same change is ada-url/idna#91, which this file is vendored from.

[codecov]

Codecov Report

❌ Patch coverage is 61.53846% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.67%. Comparing base (f841678) to head (8465053).

Files with missing lines	Patch %	Lines
src/ada_idna.cpp	61.53%	1 Missing and 9 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1251      +/-   ##
==========================================
+ Coverage   65.59%   65.67%   +0.07%     
==========================================
  Files          43       43              
  Lines        8694     8716      +22     
  Branches     3879     3887       +8     
==========================================
+ Hits         5703     5724      +21     
+ Misses        758      754       -4     
- Partials     2233     2238       +5     

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[codspeed-hq]

Merging this PR will regress 1 benchmark

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
❌ 1 regressed benchmark
✅ 49 untouched benchmarks
⏩ 4 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	SetHash	1.7 µs	1.8 µs	-6.42%
⚡	SetSearchAlternatingLength	3.9 µs	3.8 µs	+3.87%
⚡	SetSearchInsertAndClear	2.4 µs	2.3 µs	+3.82%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing Arawoof06:bidi-domain-every-label (8465053) with main (f841678)}

Footnotes

1. 4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[lemire]

I encourage you to submit the PR to idna and we then get the fix from idna.

It is too messy if we change everything at once.

[lemire]

@anonrig I recommend closing this PR, not that the change is not welcome, but just because it is duplicated effort.